code: def test__regressor_names():
      """Test that function allows invalid column identifier."""
      reg_names = _regressor_names("1_cond", "glover")
      assert reg_names[0] == "1_cond"
  
imports: import warnings
  import numpy
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_almost_equal, assert_array_equal
  from nilearn.glm.first_level.hemodynamic_models import _calculate_tr, _hrf_kernel, _regressor_names, _resample_regressor, _sample_condition, compute_regressor, glover_dispersion_derivative, glover_hrf, glover_time_derivative, orthogonalize, spm_dispersion_derivative, spm_hrf, spm_time_derivative
label_desc: Use image node_id 23 for calling a global function with example usage: test__regressor_names() without return types